One of the today's main environmental pollution problem is an acidic emissions of sulfur-containing components from coal power plants and from metallurgical smelting plants. In the extraction of metals from ores or in the combustion of fuels, sulfur dioxide is often one of the products of the process and appears in the waste gases normally vented to the atmosphere. Accordingly, the pollution of the atmosphere by sulfur dioxide is one of the greatest air pollution problems facing mankind today. As oil resources dwindle and a chain of nuclear plant disasters casts doubt on their safety, burning of sulfur-containing fuel (coal, natural gas and peat) is expected to increase.
U.S. Pat. No. 8,852,540 describes a continuous method and apparatus for flue gas desulfurization using molten carbonate melt. The process comprises chemical or electrochemical regeneration of a carbonate melt by producing a sulfur-containing vapor from the molten mixture of carbonates, sulfites and sulfates using CO as a reducing agent; releasing said sulfur-containing vapor which can be further converted into liquid and solid phase materials and collected for further use.
Processing and clearing of flue gas from modern smelting units, gas that is relatively rich in sulfur (more than 5-10% SO2) has been used successfully to produce sulfuric acid or elemental sulfur. Unfortunately, in some processes, such as reverberatory or blast processes and in coal power plants, exhaust gases contain relatively low sulfur content (less than 2-3% SO2) and its processing is extremely difficult and not economically viable. These gases emitted into the atmosphere, contaminating it and forming acid rains. Purification and neutralization of gases with low content of sulfur is a priority problem.